Sir Alex Ferguson praised "a championship performance" by Manchester United after they came from behind three times to beat Newcastle United 4-3 thanks to Javier Hernández's 90th-minute winner on the same day their title rivals Manchester City lost at Sunderland.

United are now seven points clear of their neighbours and the City manager, Roberto Mancini, could be in trouble with the Football Association after he said that the referee for the 1-0 defeat at the Stadium of Light, Kevin Friend, and his linesmen "may have eaten too much for Christmas", adding that "it wasn't a great performance from them".

Ferguson, too, may have to face an FA charge after he confronted the referee, Mike Dean, and two of his officiating team after Newcastle's second, awarded as a Jonny Evans own-goal after first being ruled offside.

The United manager's delight at this victory will, however, be tempered by the news that he will be without Wayne Rooney for up to three weeks because of a knee injury suffered in training.

Ferguson complimented his side's bravery: "It's a great quality to have – once again they have proved their courage," he said. "The statement was the performance, never mind where we are at this moment in time. That was a championship performance. It puts us in a good position but we always say December is a month that tells you everything. We come to 1 January at Wigan still top of the league."

Evans's own goal came after 28 minutes when he touched in Danny Simpson's cross. Jake Collin, the assistant referee, flagged Papiss Cissé as offside, before Dean, under pressure from Newcastle, changed the decision. Ferguson said: "Mike Dean doesn't have the benefit of what I have got in terms of video replay. It's clear. The linesman correctly whistled for offside because Ba [actually Cissé] was in an offside position and he pulled Jonny Evans' arm. If that's not interference then what is? And that was the point I was making to Mike Dean.

"He said it was an own goal, so it didn't matter that the player was offside but when you see the video replay he is certainly interfering with the play. The referee changed the linesman's mind. If you see it again, and the referee can't see it, that's where his linesman has to come into it." Dean must include the incident in his report for Ferguson to potentially face a charge.

James Perch had opened the scoring before Evans scored at both ends approaching the half hour mark. Further strikes from Patrice Evra and Sunderland's Cissé preceded Hernández's winner.

Of Rooney's injury Ferguson, who was also without Danny Welbeck, Ashley Young and Phil Jones, said: "Wayne had a volley [on Tuesday] towards the end of training and he's tweaked the ligament in the back of his knee. He could be out for two or three weeks which is unfortunate because I thought after his [disappointing] performance on Sunday he could be brilliant. You know you don't have two performances like Wayne did on Sunday."

"Danny Welbeck [fell] ill in the team hotel [on Tuesday] and Ashley Young got injured in training also. Phil Jones got his injury last week against Swansea. We couldn't risk Vida [Nemanja Vidic, an unused replacement] after his first game at Swansea, he had some soreness in his knee after being out for so long which is to be expected."Mancini, meanwhile, was incensed that the referee not to blow for a foul by Craig Gardner in the build up to Adam Johnson's winner for Sunderland. "The referee [Kevin Friend] may have had too much to eat for Christmas. He and the linesman too. It wasn't a great game from them. That's the problem we have sometimes in football. I don't see how the referee can't see the foul in the build up. I don't know how."

It was a third consecutive defeat for City at the Stadium of Light and Mancini said: "Sunderland are turning into a bit of a bogey side. I had no idea what was happening at Old Trafford butthey [United] are a great team and, at the moment, they are getting better results than we are."